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| Author | Liebermann, D.G.; Biess, A.; Friedman, J.; Gielen, C.C.A.M.; Flash, T. | ||||
| Title | Intrinsic joint kinematic planning. I: reassessing the Listing's law constraint in the control of three-dimensional arm movements | Type | Journal Article | ||
| Year | 2006 | Publication | Experimental Brain Research | Abbreviated Journal | Exp Brain Res |
| Volume | 171 | Issue | 2 | Pages  |
139-154 |
| Keywords | Adolescent; Adult; Analysis of Variance; *Arm; Biomechanics; Eye Movements/*physiology; Humans; Joints/*physiology; Male; Movement/*physiology; *Musculoskeletal System; Orientation/*physiology; Posture | ||||
| Abstract | This study tested the validity of the assumption that intrinsic kinematic constraints, such as Listing's law, can account for the geometric features of three-dimensional arm movements. In principle, if the arm joints follow a Listing's constraint, the hand paths may be predicted. Four individuals performed 'extended arm', 'radial', 'frontal plane', and 'random mixed' movements to visual targets to test Listing's law assumption. Three-dimensional rotation vectors of the upper arm and forearm were calculated from three-dimensional marker data. Data fitting techniques were used to test Donders' and Listing's laws. The coefficient values obtained from fitting rotation vectors to the surfaces described by a second-order equation were analyzed. The results showed that the coefficients that represent curvature and twist of the surfaces were often not significantly different from zero, particularly not during randomly mixed and extended arm movements. These coefficients for forearm rotations were larger compared to those for the upper arm segment rotations. The mean thickness of the rotation surfaces ranged between approximately 1.7 degrees and 4.7 degrees for the rotation vectors of the upper arm segment and approximately 2.6 degrees and 7.5 degrees for those of the forearm. During frontal plane movements, forearm rotations showed large twist scores while upper arm segment rotations showed large curvatures, although the thickness of the surfaces remained low. The curvatures, but not the thicknesses of the surfaces, were larger for large versus small amplitude radial movements. In conclusion, when examining the surfaces obtained for the different movement types, the rotation vectors may lie within manifolds that are anywhere between curved or twisted manifolds. However, a two-dimensional thick surface may roughly represent a global arm constraint. Our findings suggest that Listing's law is implemented for some types of arm movement, such as pointing to targets with the extended arm and during radial reaching movements. | ||||
| Address | Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, 69978, Ramat Aviv, Israel. dlieberm@post.tau.ac.il | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 0014-4819 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:16341526 | Approved | no | ||
| Call Number | Penn State @ write.to.jason @ | Serial | 18 | ||
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| Author | Park, J.; Pazin, N.; Friedman, J.; Zatsiorsky, V.M.; Latash, M.L. | ||||
| Title | Mechanical properties of the human hand digits: Age-related differences | Type | Journal Article | ||
| Year | 2014 | Publication | Clinical Biomechanics | Abbreviated Journal | |
| Volume | 29 | Issue | 2 | Pages |
129–137 |
| Keywords | hand; aging; friction; apparent stiffness; damping | ||||
| Abstract | Background Mechanical properties of human digits may have significant implications for the hand function. We quantified several mechanical characteristics of individual digits in young and older adults. Methods Digit tip friction was measured at several normal force values using a method of induced relative motion between the digit tip and the object surface. A modified quick-release paradigm was used to estimate digit apparent stiffness, damping, and inertial parameters. The subjects grasped a vertical handle instrumented with force/moment sensors using a prismatic grasp with four digits; the handle was fixed to the table. Unexpectedly, one of the sensors yielded leading to a quick displacement of the corresponding digit. A second-order, linear model was used to fit the force/displacement data. Findings Friction of the digit pads was significantly lower in older adults. The apparent stiffness coefficient values were higher while the damping coefficients were lower in older adults leading to lower damping ratio. The damping ratio was above unity for most data in young adults and below unity for older adults. Quick release of a digit led to force changes in other digits of the hand, likely due to inertial hand properties. These phenomena of “mechanical enslaving” were smaller in older adults although no significant difference was found in the inertial parameter in the two groups. Interpretations The decreased friction and damping ratio present challenges for the control of everyday prehensile tasks. They may lead to excessive digit forces and low stability of the grasped object. |
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| ISSN | 0268-0033 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | Serial | 73 | |||
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| Author | Lerner, O.; Friedman, J.; Frenkel-Toledo, S. | ||||
| Title | The effect of high-definition transcranial direct current stimulation intensity on motor performance in healthy adults: a randomized controlled trial | Type | Journal Article | ||
| Year | 2021 | Publication | Journal of NeuroEngineering and Rehabilitation | Abbreviated Journal | J NeuroEngineering Rehabil |
| Volume | 18 | Issue | Pages |
103 | |
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| ISSN | 1743-0003 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | Serial | 109 | |||
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| Author | Bezalel, G.; Nachoum Arad, G.; Plotnik, M.; Friedman, J. | ||||
| Title | Voluntary step execution in patients with knee osteoarthritis: Symptomatic vs. non-symptomatic legs | Type | Journal Article | ||
| Year | 2021 | Publication | Gait & Posture | Abbreviated Journal | Gait Posture |
| Volume | 83 | Issue | Pages |
60-66 | |
| Keywords | Accidental falls; Gait; Knee; Osteoarthritis; Voluntary step | ||||
| Abstract | BACKGROUND: Individuals with osteoarthritis fall at a greater rate than the general population, likely as a result of weakness, pain, movement limitations, and a decline in balance. Due to the high prevalence of osteoarthritis in the population, understanding the mechanisms leading to greater fall risk is an important issue to better understand. RESEARCH QUESTION: What is the influence of unilateral knee osteoarthritis on the characteristics of performing a voluntary step (i.e., similar to that performed to avoid a fall after a perturbation), compared to healthy age-matched controls? METHODS: Case-control study performed in a Health maintenance organization physical therapy clinic. The research group consisted of a referred sample of 21 patients with unilateral knee osteoarthritis. The control group consisted of 22 age-matched healthy individuals. All participants were over 65 years of age. Participants were excluded if they had a surgical procedure to back or lower limb within one year before testing, oncological or neurological disease or a deficit in tactile sense. Movements were performed with and without dual tasking. MEASUREMENTS: Duration of the initiation phase (cue to step initiation), preparatory phase (step initiation to foot off) and swing phase (foot off to foot contact). RESULTS: In the preparatory phase and swing phase, the osteoarthritis group moved more slowly than the control group, and these differences were larger for forward compared to backward movements. Dual-tasking slowed responses in the pre-movement initiation stage across groups. SIGNIFICANCE: The differences in basic parameters, and the slower movements in the osteoarthritis group, are consistent with known features of osteoarthritis, being a disease commonly regarded as primarily “mechanical”, and are likely to increase fall risk. These response deficits suggest we should take advantage of advanced rehabilitation techniques, including cognitive loading, to help prevent falls in older adults with osteoarthritis. | ||||
| Address | Dept. Physical Therapy, Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. Electronic address: jason@tau.ac.il | ||||
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| Language | English | Summary Language | Original Title | ||
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| ISSN | 0966-6362 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:33080457 | Approved | no | ||
| Call Number | Serial | 107 | |||
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| Author | Raveh, E.; Portnoy, S.; Friedman, J. | ||||
| Title | Adding vibrotactile feedback to a myoelectric-controlled hand improves performance when online visual feedback is disturbed | Type | Journal Article | ||
| Year | 2018 | Publication | Human Movement Science | Abbreviated Journal | Hum Mov Sci |
| Volume | 58 | Issue | Pages |
32-40 | |
| Keywords | Myoelectric prostheses; Sensorimotor control; Upper limb amputation; Visual feedback | ||||
| Abstract | We investigated whether adding vibrotactile feedback to a myoelectric-controlled hand, when visual feedback is disturbed, can improve performance during a functional test. For this purpose, able-bodied subjects, activating a myoelectric-controlled hand attached to their right hand performed the modified Box & Blocks test, grasping and manipulating wooden blocks over a partition. This was performed in 3 conditions, using a repeated-measures design: in full light, in a dark room where visual feedback was disturbed and no auditory feedback – one time with the addition of tactile feedback provided during object grasping and manipulation, and one time without any tactile feedback. The average time needed to transfer one block was measured, and an infrared camera was used to give information on the number of grasping errors during performance of the test. Our results show that when vibrotactile feedback was provided, performance time was reduced significantly, compared with when no vibrotactile feedback was available. Furthermore, the accuracy of grasping and manipulation was improved, reflected by significantly fewer errors during test performance. In conclusion, adding vibrotactile feedback to a myoelectric-controlled hand has positive effects on functional performance when visual feedback is disturbed. This may have applications to current myoelectric-controlled hands, as adding tactile feedback may help prosthesis users to improve their functional ability during daily life activities in different environments, particularly when limited visual feedback is available or desirable. | ||||
| Address | Physical Therapy Department, Sackler Faculty of Medicine, Tel Aviv University, Israel. Electronic address: jason@post.tau.ac.il | ||||
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| Language | English | Summary Language | Original Title | ||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0167-9457 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | PMID:29353091 | Approved | no | ||
| Call Number | Serial | 88 | |||
| Permanent link to this record | |||||